The present invention relates to floor mats designed for being laid upon existing flooring, such as used in vehicles for protecting carpeting. More specifically, the present invention relates to an improved floor mat provided with carpeting, and a process for making same.
Conventional floor matting, as used in runners for commercial and residential flooring, involves laminating a web of carpeting upon a complementary web of rubber-like backing material. The two webs are adhered to each other using heat and/or chemical adhesives as is well known in the art. Such technology has been considered unsuitable for vehicle floor mats due, among other things, to the tendency for the carpeting to become detached from the backing material during normal use, especially at the peripheral edges.
Thus, overlay mats or lining carpets for vehicles are conventionally beaded. This beading is generally not detrimental to the desired flexibility of the carpet edge. However, such beadings are costly to produce and, moreover, have a considerable tendency to become soiled. The lifetime of such a carpet mat is usually limited, typically because a beading has been damaged.
In view of this problem, vehicle carpet mats are conventionally produced by first producing a hard-wearing carrier material from plastic by injection molding. A decorative material, such as carpet cut to size, has to be fastened into this carrier material in a further operation, typically using chemical adhesives or heat. So that cutting tolerances in the carpet can be absorbed or colored, but also to make a reinforced border available for the carpet edge, the carrier material is preferably produced with an undercut. This undercut, on the one hand, solves the problem of the cutting tolerances, but, on the other hand, creates a new problem.
Injection molds with corresponding slide systems are typically required to produce a clean undercut with an overhang which is suitable for covering tolerances of at least several millimeters. Only with the aid of such slide systems is it possible to remove the ready-molded carrier material from the mold damage free. Moreover, carpet edges bordered in this way prove to be insufficiently flexible. Furthermore, the operation of gluing the decorative material onto the carrier material represents an additional increase in price of the final product, and the adhesive power of the glue has been known to decrease over time and with extended use. Another drawback of such techniques is that apertured grommets used to releasably secure these mats to the vehicle floor must be added by hand post-molding.
U.S. Pat. No. 4,491,556 discloses a method and a device for producing a carpet mat, with an injection-molding unit including two molds. At least one of the molds has a cavity for forming the edges of a mat underlay. The method involves fitting a carpet into this receiving depression and injecting a thermoplastic resin into the space behind the carpet to provide a mat underlay which is simultaneously connected to the carpet. The '556 patent recognizes the problems inherent with injection molding carpet mats, including that the flowing resin migrates into the carpeting, and that the heat of the mold thins or otherwise degrades the carpeting during the molding process. While the '556 disclosure allegedly resolved this problem, this technique has not been adopted by the commercial vehicle mat manufacturing industry.